"Stoners design allowed the bolt to engage directly to the barrel, thus cutting out the middle man (the receiver). I think that design was revolutionary and took some thinking on his part."
...and yet again people completely forget about the massive (as in, almost the entire idea) contributions of one Melvin Johnson, of Johnson Rifle fame, specifically to one Eugene Stoner during his assault/sporting rifle development project. It was veritably a joint venture, for which Johnson gets almost no modern credit (sort of like all the other schmoes on Kalashnikov's design team that never got historic recognition, though possibly nice apartments). The multi-lug bolt was entirely his idea (the weirdo gas system since copied by exactly no other designs was all Stoner, though)
"Remington model 8 w/detachable 15rd mag - rifle..."
Billy Shears is right; a long-recoil action (Model 8 as well as the A5) is a loathsome option when dealing with medium or weaker strength cartridges with very short recoil impulses. There is no reason to keep the breech locked for so long, especially when it means you have so much moving mass to deal with. Now, in a heavy 50BMG like the GM6 Lynx, with a very long pressure duration and massive recoil inertia, you need a heavy mass with a long length of travel to soak up that energy --but it isn't needed for a lower power gun. But in Browning's day, action timing was still an evolving science (see the Breda 30) and the long-recoil setup made for a very safe, reliable, and adaptable design (if a bit rough on the shoulder)
Browning was brilliant at the three types of weapons which dominated his era; manually-operated long arms (O/U, Winchesters), handguns (1903, 1911, portions of the Hi Power), and heavy/light machineguns (1885, 1919, BAR). He was not nearly as prolific at autoloading rifles. I suspect this was not so much due to any lack of genius, as a decided lack of appreciation or inspiration for such items in his day. The ZH29 and Garand were very cutting edge technology, from an entirely new generation of inventors, and were (obviously) only in the earliest stages of development by the time Browning's health was failing. The 'gun technology infrastructure' in existence for Browning to build upon was largely that of massive Maxim/Schwarzelose sideplate machine guns, which were more tractor than gun. Much like early engines and other machines, these relied on large, complex, heavy, large (again), and inefficient methods of locking and manipulating the breech. Modularity and multi-role parts were an unknown. Levers, cams, cogs, toggles, and gears were "hip," the more the better.
In that respect, Browning's designs were often glaringly simple for the time. But compared to the advances of the next generation of designers, they were still far too unrefined to compete (with the exception of the side-plate designs, which were both very modular and efficient, while not sacrificing the reliability of stalwart competition like the Vickers, few of his lasting contributions still stand out amongst the field of modern options, which is hardly unexpected). The M2, 1911, Superposed, M37, and A5 are still made, which is testament to their objective sufficiency as excellent weapons, but aside from maybe the M2 (which has had very compelling competition from Soviet-bloc 12.5 guns for decades that Americans are simply unaware of in their praises of its absolute superiority) these platforms have gradually become supplanted by newer designs that are improved in various ways (cost, complexity, weight, ease of handling, ergonomics, etc.)
"Wouldn't that be cool! A modernized BAR, firing 7.62 NATO, lighter weight, higher rate of fire. Who wouldn't want one!"
It's actually called an FND, or possibly an MAG58. Both are massive improvements on the very concept of the BAR, which while a new idea for a staid US military, was based on requirements borne of very flawed reasoning. Way too heavy/powerful for real mobile use like a battle (let alone assault) rifle, way too small a magazine capacity for efficient fire volume, and lack of a removable barrel precluded its ability to provide any kind of sustained fire. The semi-auto version made the gun even more poorly suited to the obvious LMG role the gun was a fit for. After version 5.0 or whatever they got up to, they eventually had a pistol-gripped machinegun with a rate reducer, replaceable barrel (with the bipod mounted to the gas tube), with dust-protection measures, and in the new NATO standard 308 chambering. FNH called this product the FND, and there were even experiments by the Swedes with a belt-fed conversion (since capacity was still very lacking, though its FAL mags were common to the much lighter rifles that were unable to deliver sustained full auto volume fire). Modernize the overall receiver layout and make it belt fed and you start getting close to what the MAG58 was.
I've always found it funny how much we Americans was poetic about the BAR. Seemed like everyone always said "granddaddy said it was the greatest," even though it was constantly being revised in the hopes of improvement, and was replaced almost immediately when something else came along (even something as lousy as the M60), never to be seen again for the most part. Now that I have my very own FND-A1 parts kit, I can see why. These guns are absolute tanks. The weight and size of the receiver is up there with the even more impractical 1st gen LMG's like the Hotchkiss Portative (only four years older), only more complicated. The operating parts themselves are absolutely enormous compared to what we are used to seeing for a 30-06-class cartridge gun; the bolt assembly is over six inches long! Receiver is about 2" wide and about a foot and a half, before you stick a barrel or stock on it. The BAR had elegant lines (when seen from the side) but it handles like a 5:4 scale rifle; it's just too big in every way, especially for the role it was intended (mobile infantry, as opposed to individual supporting machine gunner). I can see why the Madsen got as many customers as it did, despite the odd appearance (until the German recoil guns came on)
TCB